Per NFL Network's Tom Pelissero, the Cowboys will pay Neal $5 million on a one-year deal.
The Cowboys have made a number of additions on defense since the start of free agency, though their biggest move was re-signing quarterback Dak Prescott to a four-year, $160 million contract.
Defense was a significant problem for Dallas in 2020. That unit ranked 23rd in Football Outsiders' DVOA metric and 28th in points allowed.
Xavier Woods, who has been the Cowboys starting free safety for the past three seasons, is currently a free agent. Neal could take over as the starter in 2021 if the team decides not to re-sign Woods.
Neal joins defensive tackles Carlos Watkins and Brent Urban and defensive end Tarell Basham as offseason signees for the Cowboys. He played 15 games last season after appearing in a combined total of four the previous two years because of injuries.
A 2017 Pro Bowler, Neal spent the past five seasons with the Atlanta Falcons. The 25-year-old has recorded at least 100 combined tackles every season he's played at least 14 games (three times). He set a career high with nine tackles for loss and three quarterback hits in 2020.